third_party/WebKit/Source/platform/audio/Reverb.h

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef Reverb_h
#define Reverb_h

#include <memory>
#include "platform/audio/ReverbConvolver.h"
#include "platform/wtf/Allocator.h"
#include "platform/wtf/Noncopyable.h"
#include "platform/wtf/Vector.h"

namespace blink {

class AudioBus;

// Multi-channel convolution reverb with channel matrixing - one or more
// ReverbConvolver objects are used internally.

class PLATFORM_EXPORT Reverb {
  USING_FAST_MALLOC(Reverb);
  WTF_MAKE_NONCOPYABLE(Reverb);

 public:
  enum { kMaxFrameSize = 256 };

  // renderSliceSize is a rendering hint, so the FFTs can be optimized to not
  // all occur at the same time (very bad when rendering on a real-time thread).
  Reverb(AudioBus* impulse_response_buffer,
         size_t render_slice_size,
         size_t max_fft_size,
         bool use_background_threads,
         bool normalize);

  void Process(const AudioBus* source_bus,
               AudioBus* destination_bus,
               size_t frames_to_process);
  void Reset();

  size_t ImpulseResponseLength() const { return impulse_response_length_; }
  size_t LatencyFrames() const;

 private:
  void Initialize(AudioBus* impulse_response_buffer,
                  size_t render_slice_size,
                  size_t max_fft_size,
                  bool use_background_threads);

  size_t impulse_response_length_;
  // The actual number of channels in the response.  This can be less
  // than the number of ReverbConvolver's in |m_convolvers|.
  unsigned number_of_response_channels_;

  Vector<std::unique_ptr<ReverbConvolver>> convolvers_;

  // For "True" stereo processing
  scoped_refptr<AudioBus> temp_buffer_;
};

}  // namespace blink

#endif  // Reverb_h